feat: add certificate management module with image upload

- Add Certificate + CertificateCategory models with full CRUD API
- Image upload via base64 data URL stored in Text column
- Certificate fields: title, issuer, issue_date, expiry_date, image, description
- Frontend: card grid with category sidebar filter, create/edit dialog
- Include certificates in data backup/export
- Fix hasPhaseParent optimization in GoalDetailPage

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/app/schemas/certificate.py

@@ -0,0 +1,79 @@
+"""证书 Schema"""
+from pydantic import BaseModel, Field, field_validator
+from datetime import date, datetime
+from typing import Optional, List
+
+
+# ============ 证书分类 Schema ============
+
+class CertificateCategoryBase(BaseModel):
+    name: str = Field(..., max_length=50)
+    icon: str = Field(default="medal", max_length=50)
+    color: str = Field(default="#FFB7C5", max_length=20)
+    sort_order: int = Field(default=0)
+
+
+class CertificateCategoryCreate(CertificateCategoryBase):
+    pass
+
+
+class CertificateCategoryUpdate(BaseModel):
+    name: Optional[str] = Field(None, max_length=50)
+    icon: Optional[str] = Field(None, max_length=50)
+    color: Optional[str] = Field(None, max_length=20)
+    sort_order: Optional[int] = None
+
+
+class CertificateCategoryResponse(CertificateCategoryBase):
+    id: int
+    uuid: Optional[str] = None
+
+    class Config:
+        from_attributes = True
+
+
+# ============ 证书 Schema ============
+
+class CertificateBase(BaseModel):
+    title: str = Field(..., max_length=200)
+    category_id: Optional[int] = None
+    image: Optional[str] = None
+    issuer: Optional[str] = Field(None, max_length=200)
+    issue_date: Optional[date] = None
+    expiry_date: Optional[date] = None
+    description: Optional[str] = None
+    sort_order: int = Field(default=0)
+
+
+class CertificateCreate(CertificateBase):
+    pass
+
+
+class CertificateUpdate(BaseModel):
+    title: Optional[str] = Field(None, max_length=200)
+    category_id: Optional[int] = None
+    image: Optional[str] = None
+    issuer: Optional[str] = Field(None, max_length=200)
+    issue_date: Optional[date] = None
+    expiry_date: Optional[date] = None
+    description: Optional[str] = None
+    sort_order: Optional[int] = None
+
+    @property
+    def clearable_fields(self) -> set:
+        return {"description", "category_id", "image", "issuer", "issue_date", "expiry_date"}
+
+
+class CertificateListResponse(CertificateBase):
+    id: int
+    uuid: Optional[str] = None
+    created_at: datetime
+    updated_at: datetime
+    category: Optional[CertificateCategoryResponse] = None
+
+    class Config:
+        from_attributes = True
+
+
+class CertificateDetailResponse(CertificateListResponse):
+    pass